1. Field of the Invention
The present invention relates to a reciprocating piston type compressor used in a vehicle air-conditioning system, and more particularly, to a compressor housing construction.
2. Description of the Related Art
There are two typical types of reciprocating piston type compressors. The first type compresses refrigerant gas in a bore with one end, or head, of a piston while the second type compresses gas with both ends, or both heads, of a piston.
A compressor employing double-headed reciprocating pistons typically has a pair of cylinder blocks fastened to each other by a plurality of bolts. A plurality of bores is formed in each cylinder block at aligned positions with a predetermined space defined between them. A reciprocal double-headed piston is located in each pair of aligned bores. A swash plate is mounted on a rotary shaft between the two blocks to reciprocate the pistons. A pair of thrust bearings enables the swash plate to rotate with respect to the cylinder blocks.
In this prior art compressor, the bearing races are deformed when the bolts are tightened to secure the cylinder blocks to each other. The deformation of the bearing races absorbs dimensional tolerance of the two cylinder blocks, the swash plate, and the two thrust bearings in the axial direction.
However, since rotating bodies, such as balls or rollers are retained by the bearing races, deformation of the races is undesirable for smooth rotation of the rotating body, that is, smooth rotation of the bearings. A large amount of deformation will interfere with smooth rotation of the bearing and causes an increase in power loss. Thus, in conventional compressors, a large deformation of the bearing races results in low supporting rigidity of the swash plate and vibration and noise during operation. Generation of vibration and noise in the compressor may lead to resonance with other parts of the vehicle and amplify the noise.
In an attempt to overcome this problem in the prior art, various swash plates, cylinder blocks, and thrust bearings having different axial dimensions were selected and assembled to one another to offset the dimensional tolerance between each component. However, assembly of the compressor was burdensome and resulted in an increase in manufacturing costs.